RESUMO
PURPOSE: To evaluate the early histological effects of the intravesical instillation of platelet-rich plasma (PRP) in rabbit models of interstitial and hemorrhagic cystitis. METHODS: Thirty-six rabbits were classified into 6 groups: saline (S), S+PRP, hydrochloric acid (HCl), HCl+PRP, cyclophosphamide (CyP), and CyP+PRP. At 48 hours after induction, PRP was prepared and intravesically administered to the S+PRP, HCl+PRP, and CyP+PRP groups. Bladder sections were stained with toluidine blue for mast cell counting and with hematoxylin and eosin for histopathology and mitotic index determination. The proliferation index was determined by proliferating cell nuclear antigen (PCNA) immunolabeling. The nonparametric Mann-Whitney U-test was used for statistical analysis. RESULTS: No abnormalities were observed in the S group, whereas increased interstitial edema and increased average mitotic and proliferation indices were observed in the S+PRP group (P=0.023, P=0.004, and P=0.009, respectively). Intense epithelial loss, hemorrhage, and leukocyte infiltration were detected in the HCl and HCl+PRP groups, whereas a significantly increased average mitotic index was observed in the HCl+PRP group (P=0.002). When compared with its CyP counterpart, a significant reduction in hemorrhage and an increase in leukocyte infiltration and mitotic index were observed in the CyP+PRP group (P=0.006, P=0.038, and P=0.002, respectively). In addition, PCNA staining revealed a significantly increased proliferation index in the HCl+PRP and CyP+PRP groups (P=0.032 and P=0.015, respectively). CONCLUSIONS: The intravesical instillation of PRP increased the mitotic index in the saline and cyclophosphamide groups while decreasing macroscopic bleeding.